1. Field of the Invention
Algorithms and interfaces for the analysis of recorded video from multiple cameras in multiple locations are presented. Using these techniques a summary of video from multiple cameras can be used to create a storyboard of all activity with emphasis on events of importance. The summary can be used to access the recorded video.
2. Description of the Related Art
Video surveillance systems are common in commercial, industrial, and residential environments although limited human attention and the number of video streams constrains the cost efficiency and effectiveness of such systems. Identifying activity of interest within synchronized video streams from a set of security cameras is difficult due to the quantity of video data and the lack of authored metadata or indexing. Yet security personnel need to identify activities of interest and determine interrelationships between activities in different video streams. They must develop an understanding of the sequence of actions that led to or happened after a particular incident.
For example, a video security system in an office building continuously records activity from multiple cameras. If an explosion occurred in the building, security people would be asked to analyze data from the video cameras to determine the cause of the explosion. This would require searching through hours of data from multiple cameras before the time of the explosion to determine the cause.
Manga visual video summaries (see U.S. Pat. No. 6,535,639) were originally designed to provide interactive storyboards for edited video, to work with unedited video and to support multiple synchronized streams of video. The original Manga summaries relied on a camera operator or video editor to switch among several cameras or video shots to break up the video into segments. Other video summaries have similar problems, Yeung, M., and Yeo, B-L., “Video Visualization for Compact Presentation and Fast Browsing of Pictorial Content,” in IEEE Trans. Circuits and Sys. for Video Technology, Vol 7, No. 5, pp. 771-785, October 1997.
A number of different approaches for determining activity are given in Chueng, S.-C. S. and Kamath C. Robust Techniques for Background Subtraction in Urban Traffic Video. Video Communications and Image Processing, SPIE Electronic Imaging, San Jose, 2004. Keyframe piles are described in Girgensohn A., Boreczky J., Chiu P., Doherty J., Foote J., Golovchinsky G., Uchihashi S., and Wilcox L., A Semi-Automatic Approach to Home Video Editing. In Proceedings of UIST '00, ACM Press, pp. 81-89, 2000. Maps were used in the Space Time Browser to select video, see U.S. patent application Ser. No. 10/126,555, Publication Number 20030197731.